I am not sure I understand what they are proposing. If it is what I think it is, it is incorrect and does nothing for you. From what you put, they are wanting to blow cellulose and also use fiberglass batts? This makes 0 sense and not even sure how or why they would do that. Also r26 is a dream. The most you can possibly hit with that combination is an r20.

I am assuming you mean they will blow closed cell foam first and then use r13 batts. That would be roughly 2.5" of closed cell foam and then 3.5" of batts, which gets you close to that r26, and also makes sense with the price you listed. However Do I think you should do this? No, I do not. You are FAR better to install rigid insulation on the exterior of your studs and use air tight sheathing instead of closed cell spray foams. Closed cell will seal up the stud bays and make them air tight, but it does nothing for thermal bridging and does not seal up places such as top and bottom plates.
Also, the r26 they claim is only cavity space insulation values, and not clear wall value. Due to framing and thermal bridigng, you can expect to reduce that number by 15-20% for your clear wall value. Adding exterior insulation keeps your r value the same for the cavity, but increases the areas where you have an r1, whcih is at every single stud, header and framing member in your wall.

For zone 5, here is what I find is the go too wall assembly that will perform extremely well, is cost effective, and does not rely on spray foams to seal things up.

Assuming they have not framed the walls, then I would recommend as such: use Huber ZIP exterior sheathing with taped joints. This will give you an exterior air and water tight barrier everywhere on your wall, and not just in the stud bays. They omit Tyvek. Install 1-1.5" of XPS foam sheathing over the sheathing to give your shelf a thermal break and an r5 to r7.5 boost. Your r1 studs now change to r8.5 (if using 1.5" XPS) and your stud bays now change from r19/20 to about r27. Your whole wall average increases as you can see since you have higher r over your studs than before. This also continues to create an air tight shell. At this point, you can fill your stud bays with whatever you want and it will perform much better. I would still recommend a blown cellulose or fiberglass, however going with batts would also work, just not quite as effective.

Air sealing if far more important than higher r value. Focus on this, and then put money into boosting the r value. Keep in mind, the more r value and air sealing you add, you can start to reduce other costs such as your mechanical system. You install a smaller mechanical system, which means lower upfront cost there (helps to offset added exterior sheathing) but more importantly lower heating/cooling costs for the life of the home.

As for the ceiling, it is just as important as the walls. these need air sealed as well. I find one of the best and easiest ways is to have them do an "attic seal" with open cell spray foam. All they do is spray all penetrations where they come through the drywall in the attic. They only need a couple inches, and not over the entire ceiling, just at the penetrations. This includes electrical, plumbing, framing, etc. If you have can lighting, wrap them in some fiberglass batts and spray around them to form a cocoon. Cans are extremely leaky, even so called "air tight cans".
After this, then BLOW insulation in, do not use batts. And r38 is very low. Blowing in thicker insulation is pennies per inch typcailly. Bump it up to atleast r50, better yet go r60.

Invest in GOOD windows with good u values. Shoot for u values of .30 and lower. Consider windows with higher SHGC values (.45 and higher) on south windows if you have good overhangs. These sorts of tweaks typically do not cost anything.

Bumping of values mentioned about can shift your "rule of thumb" HVAC sizing (I will say, rule of thumbs are completely inaccurate and you need to have a manual J preformed for your equipment, espeically if you increase r values) from 1 ton of heating /1000 sqft to about 1500 sqft. This means you can decrease your equipment by 1 to 2 tons easily. My home, which similar square footage in a higher heating zone 6 only needs 24k btu for heating, which means it costs about $45 in Jan to heat 3800 sqft. It cost me $16 to cool my home this last month with high 80s and low 90s daily with a set point at 72. It does not have much higher r values than I recommended above. infact its very similar given the different zones. But it has been meticulously air sealed and then r30 in the walls and r60 in the roof with triple pane glass.

You are building a million dollar home. I assume your finishes, both exterior and interior are high end and quite nice. You would be doing yourself a serious diservice by not putting more money into the shell of your home since after all, that is what protects you and yours, and also is the ONLY place you can see financial payback. Its your money, but these are my proven recommendations to your questions. I am confident my recommendations will cost roughly the same as what they are giving you as an upgrade for your foam. Also eheck with local utilties, they may ahve rebates for higher performing homes. Around here, if you build to Energy Star 3.0 you can get up to around $6k back in rebates. Worth looking into.

"Your r1 studs now change to r8.5 "

If 1.5" of XPS has a total R value of R-7.5 (1.5" x R-5), why would 5.5" of softwood only have a total R value of R-1?

Why would it not be R-7 (5.5" x R-1.27) and the R-7 studs change to R-14.5?

This post was edited by Renovator8 on Wed, Aug 21, 13 at 10:46

r value of wood is approx. 1.25 to get technical. My items above can get way more technical than what I put, but it breaks it down to a common base of easy explaination. But you are correct, I did not calc the thickness of the wood but rather the foam only, so indeed the areas of the stud would be closer to r14 while stud bases are still in the mid r20s. Change to 24" oc framing, and the whole wall average increases more.

For reference,here are the minimum insulation requirements for New Jersey by county.

lzerarc's suggestions provide economical thermally efficient, i.e., moneysaving, approaches to insulation.

As noted by Renovator8, wood is not that thermally inefficient.
Softwood 2x6s have an R Value of 6.88.

The fg between floors will by itself provide an undetectable decrease in sound transmission, whether by STC or IIC. (Not to mention it is absurdly overpriced. )

It would be more efficient to work with an independent designer/architect who could spec to higher energy standards rather than ad hoc negotiating with a builder who may be wed to traditional approaches.

This post was edited by worthy on Wed, Aug 21, 13 at 11:13

The sound abatement value of insulation in floor and wall cavities is due almost entirely to it's ability to absorb sound that enters through cracks and travels to another crack thereby losing energy by bouncing off of surfaces and passing laterally through a large amount of insulation. Insulation would have little or no value in walls with doors that are not acoustically sealed.

A better sound treatment for a ceiling would be resilient channels or similar devices that allow the ceiling to absorb sound energy from the air and the structure. Such systems are typically used in multi-family housing to achieve code required sound separations. Certain kinds of thin resilient underlayment on the upper level can also help reduce structure borne sound.

Lzearc's advice is so good that I think the simplification of R per inch of studs is nitpicky but worth pointing out.

Worthy's advice on an independent energy rater/advisor would also be very wise. Getting a blower door test in the 1.5 ACH50 range will provide a much bigger comfort and energy result than agonizing over misleading and difficult to calculate R values.

Speaking of "meaningless" R values, Worthy's link is for the 2009 IECC which is probably whats required by local inspection in your area. However, you cant depend on local enforcement to ensure a comfortable and energy efficient home. A home that is built to the 2009 IECC is the poorest performing home allowed by an already outdated international law. Very few inspection departments enforce the important parts of this old code anyways. I predict some serious change in this area in the coming years but we arent there yet and people need to be putting in the planning and effort themselves if they want to have a meaningful impact in the comfort, energy efficiency and durability of a home.

The 2009 IECC is an international energy code that has now been replaced by the 2012 IECC. The current version will result in a much better home that many feel is still under the point of diminishing returns depending on the many details.

The 2012 IECC table 402.2 requires foam sheathing on stick frame construction in your climate (zones 3-5) unless your wall is double stud or has cavity insulation of R20 and up. 1" of foam sheathing will meet this requirement and I suggest you look into the ZIP+R sheathing to knock out this requirement AND lzearcs excellent suggestion of using ZIP to achieve a good wall air barrier. ZIP is certainly not a cure all either. Walls tend to leak very little compared to the many transitions in a home.

The prescriptive MINIMUM for ceiling is R49.

The MANDATORY minimum blower door test for your climate is 3 ACH50 but I think this will get lowered to 1.5 in the quickly approaching 2015 version and if you are going to be there for 20 years it may be smart to think ahead. This is likely to be the most cost-effective measure for comfort, low energy costs and durability.

These are minimums and I remember a time when people built above code and were proud of it. The fact that you are here seeking advice on such a permanent and important feature speaks volumes to your commitment to building a good home.